I was in a similar circumstance as you and I just made the decision. Last Friday I ordered a Laramie, quad cab, 4x4, 3.55 rear axle, 4 corner air suspension, Ram boxes and a few other options and for the motor I ordered the.............................pentastar!
Here's why - I was considering all three available - Hemi and diesel too. I first thoroughly evaluated my needs - this will be a daily driver, I commute about 50 miles to work and I can put as much as 20k miles on per year, I hardly ever tow, I do occasionally haul so payload is probably my biggest need.
So that all said the v6 has THE best payload numbers of the 3 motors - check the Ram webpage (The two/haul tool) if you want confirmation. I test drove all three prior to ordering and the pentastar with the 8 speed transmission is fantastic! If I didn't know better I thought it was a v8! Lots of power even in 4 wheel drive and great acceleration. Also, I suggest you really consider all the factors that come with the diesel. The following 3 factors discouraged me - 1.) $4k up charge over the V6 - in light of how the V6 performed this was a difficult justification to make; 2.) DEF fuel - an additional commitment forever - it is falling in price and is increasingly available at the pump even but still another added cost and hassle; 3.) oil changes - nearly 11 quarts of upgraded diesel grade oil and the filters although now OEM's are increasingly available still $30 to $40 per copy. That all combined was harder for me to justify the diesel. I considered the arguments regarding high resale value and the durability claims but the the pentastar for the price, the performance and the capability was too difficult to ignore. Quite frankly - I also considered the new 2015 Ford 2.7L V6 but the pentastar is naturally aspirated and by comparison a much less complex motor (one of Ward's ten best - two years running) and has a good record of durability, efficiency and low maintenance.
I hope this helps and I cannot wait to get my truck!!!!